High speed surface craft and submersible craft

ABSTRACT

A marine vessel comprising:
         at least one buoyant tubular foil; and   at least one baffle plate positioned about the perimeter of the at least one buoyant tubular foil so as to protrude into the flow of water passing by the perimeter of the at least one buoyant tubular foil, whereby to create a high-pressure zone fore of the at least one baffle plate and a low-pressure zone immediately aft of the at least one baffle plate, whereby to create a dense stream of supercavitated water immediately aft of the at least one baffle plate.

REFERENCE TO PENDING PRIOR PATENT APPLICATIONS

This patent application:

(1) is a continuation-in-part of pending prior U.S. patent applicationSer. No. 14/231,887, filed Apr. 1, 2014 by Juliet Marine Systems, Inc.and Gregory E. Sancoff for HIGH SPEED SURFACE CRAFT AND SUBMERSIBLEVEHICLE (Attorney's Docket No. JULIET-010203A04A0709 CON), which patentapplication is a continuation of prior U.S. patent application Ser. No.13/436,291, filed Mar. 30, 2012 by Gregory E. Sancoff for HIGH SPEEDSURFACE CRAFT AND SUBMERSIBLE VEHICLE (Attorney's Docket No.JULIET-010203A04A0709), which patent application:

-   -   (i) is a continuation-in-part of prior U.S. patent application        Ser. No. 12/485,848, filed Jun. 16, 2009 by Gregory E. Sancoff        et al. for FLEET PROTECTION ATTACK CRAFT (Attorney's Docket No.        JULIET-0102), which patent application in turn claims benefit        of (a) prior U.S. Provisional Patent Application Ser. No.        61/132,184, filed Jun. 16, 2008 by Gregory Sancoff for FORCE        PROTECTION ATTACK CRAFT (Attorney's Docket No. JULIET-1 PROV),        and (b) prior U.S. Provisional Patent Application Ser. No.        61/200,284, filed Nov. 26, 2008 by Gregory E. Sancoff et al. for        FLEET PROTECTION ATTACK CRAFT (F-PAC) (Attorney's Docket No.        JULIET-2 PROV);    -   (ii) is a continuation-in-part of pending prior U.S. patent        application Ser. No. 13/212,767, filed Aug. 18, 2011 by        Gregory E. Sancoff for FLEET PROTECTION ATTACK CRAFT AND        UNDERWATER VEHICLES (Attorney's Docket No. JULIET-0709), which        patent application in turn claims benefit of (a) prior U.S.        Provisional Patent Application Ser. No. 61/374,923, filed Aug.        18, 2010 by Gregory E. Sancoff for SUPERCAVITATION AIR CHANNELS        FOR BUOYANT TUBULAR FOIL (Attorney's Docket No. JULIET-7 PROV),        and (b) prior U.S. Provisional Patent Application Ser. No.        61/374,940, filed Aug. 18, 2010 by Gregory E. Sancoff for        TORPEDO EMPLOYING FRONT-MOUNTED COUNTER-ROTATING PROPELLERS AND        STEERING SPOILERS (Attorney's Docket No. JULIET-9 PROV);    -   (iii) is a continuation-in-part of prior International (PCT)        Patent Application No. PCT/US11/52642, filed Sep. 21, 2011 by        Juliet Marine Systems, Inc. et al. for FLEET PROTECTION ATTACK        CRAFT AND SUBMERSIBLE VEHICLE (Attorney's Docket No.        JULIET-01020709 PCT);    -   (iv) claims benefit of prior U.S. Provisional Patent Application        Ser. No. 61/469,127, filed Mar. 30, 2011 by Gregory E. Sancoff        for SEA-X1: SHALLOW SUBMERGED SUPER-CAVITATIONS SUBMARINE        (Attorney's Docket No. JULIET-3A PROV); and    -   (v) claims benefit of prior U.S. Provisional Patent Application        Ser. No. 61/469,143, filed Mar. 30, 2011 by Gregory E. Sancoff        for SEA-SPRINT: UNMANNED, HIGH SPEED SUPER-CAVITATIONS        SUBMERSIBLE CRAFT (Attorney's Docket No. JULIET-4A PROV);

(2) claims benefit of pending prior U.S. Provisional Patent ApplicationSer. No. 61/844,767, filed Jul. 10, 2013 by Juliet Marine Systems, Inc.and Gregory E. Sancoff for BAFFLE PLATE TO ENHANCE SUPERCAVITATIONEFFECT (Attorney's Docket No. JULIET-19 PROV); and

(3) claims benefit of pending prior U.S. Provisional Patent ApplicationSer. No. 61/876,829, filed Sep. 12, 2013 by Juliet Marine Systems, Inc.and Gregory E. Sancoff for BAFFLE PLATE TO ENHANCE SUPERCAVITATIONEFFECT (Attorney's Docket No. JULIET-20 PROV).

The thirteen (13) above-identified patent applications are herebyincorporated herein by reference.

FIELD OF THE INVENTION

This invention relates to marine vessels in general, and moreparticularly to high-speed attack and reconnaissance craft.

BACKGROUND OF THE INVENTION

The terrorist attack on the guided missile destroyer USS Cole in Adenharbor in 2000 provided a devastating example of what a small group ofterrorists can do to a modern warship with minimal resources—in the caseof the USS Cole, two terrorists in a small boat carrying a few hundredpounds of explosives came close to sinking a billion dollar warship.

The success of the attack on the Cole has given rise to another, evenmore disturbing concern—that a large number of high speed boats, eachpacked with explosives and manned by suicide bombers, could create a“small boat swarm” which could overwhelm the defenses of a warship,particularly in restricted waters where reaction time andmaneuverability may be limited. Indeed, recent wargame simulationssuggest that such swarm tactics could prove extremely effective againstnaval battle groups operating in the narrow waters of the Persian Gulf.

It is currently believed that such “small boat swarm” tactics are bestcountered with fast, similarly-sized, highly-maneuverable andheavily-armed attack craft which can establish a defensive perimeter ata safe distance from the naval battle group. To this end,appropriately-outfitted Zodiac-type craft have already been deployed forthis purpose. However, experience has shown that Zodiac-type craft areonly practical in the relatively calm waters of a harbor. This isbecause operating Zodiac-type craft at high speed in the turbulentwaters of the open sea imposes excessive physical stresses on the crewsthat can only be withstood for short periods of time. Furthermore, thedefensive perimeter should, ideally, be established at a substantialdistance from the battle group (e.g., at least 10 miles out), in orderto give the battle group sufficient time to react in the event that anyof the small boat swarm should penetrate the defensive perimeterestablished by the Zodiac-type craft. However, due to their lightconstruction, limited operating time at high speeds, and limitedfuel-carrying capacity, Zodiac-type craft are not capable of maintaininga reliable defensive perimeter so far out from the battle group. Inpractice, with Zodiac-type craft, the defensive perimeter must generallybe maintained much closer to the battle group, with the consequent lossof reaction time.

It has been suggested that attack helicopters might be used to protect anaval battle group when it is at sea or at anchor. However, attackhelicopters generally have relatively limited range and, perhaps moreimportantly, relatively limited sortie time, which effectively preventsthem from maintaining a reliable defensive perimeter a substantialdistance out from the battle group. Furthermore, attack helicoptersgenerally have substantial radar, infrared and visual “signatures”,thereby making them relatively easy to detect and target.

Thus, there is a need for a new and improved fleet protection attackcraft which can be used to maintain a defensive perimeter a safedistance out from a naval battle group. In this respect it should beappreciated that such a craft should be small, fast, highly-maneuverableand heavily-armed. Furthermore, the craft should provide a stableplatform even when running at high speed in substantial ocean swells,whereby to minimize physical stress on the crew and to provide a stableweapons platform. Further, the craft should be capable of remaining onstation for a substantial period of time, in order to maintain areliable defensive perimeter at a safe distance from the battle group.

There is also a need for a new and improved craft which can be used forreconnaissance, and/or to deliver small teams of special forces behindenemy lines and/or to extract the same. Thus, the craft should also becapable of “stealth mode” operation, i.e., it should have small radar,infrared, visual and noise signatures, thereby making it difficult todetect and target.

In addition to the foregoing, there is also a need for a new andimproved submersible vehicle (e.g., submarine, torpedo, unmanned drone,etc.) which is capable of moving through the water at high speeds.

SUMMARY OF THE INVENTION

These and other objects of the present invention are addressed by, amongother things, the provision and use of a novel fleet protection attackcraft. The novel attack craft is small, fast, highly-maneuverable andheavily-armed. The novel attack craft provides a stable platform evenwhen running at high speed in substantial ocean swells, whereby tominimize physical stress on the crew and to provide a stable weaponsplatform. And the novel attack craft is capable of remaining on stationfor a substantial period of time, in order to maintain a reliabledefensive perimeter at a safe distance from a naval battle group. Thus,the novel attack craft provides an effective means for defending againsta “small boat swarm”, by establishing a defensive perimeter at a safedistance from the battle group and thereby permitting the interception,identification, warning and, if ultimately necessary, destruction ofhostile boats long before they can approach the battle group.

In addition, the novel attack craft is also capable of “stealth mode”operation, i.e., it has small radar, infrared, visual and noisesignatures, thereby making it difficult to detect and target. Thus, thenovel attack craft also provides an effective means for conductingreconnaissance and/or for delivering small teams of special forcesbehind enemy lines and/or for extracting the same.

In addition to the foregoing, the objects of the present invention areaddressed by the provision and use of a novel submersible vehicle (e.g.,submarine, torpedo, unmanned drone, etc.) which is capable of movingthrough the water at high speeds.

In one form of the present invention, there is provided a marine vesselcomprising:

a command module;

first and second buoyant tubular foils; and

first and second struts for connecting the first and second buoyanttubular foils to the command module, respectively;

wherein the first and second buoyant tubular foils provide substantiallyall of the buoyancy required for the marine vessel;

wherein the first and second struts are pivotally connected to thecommand module and fixedly connected to the first and second buoyanttubular foils, respectively; and

wherein the first and second struts comprise substantially rigid planarstructures.

In another form of the present invention, there is provided a marinevessel comprising:

a command module;

first and second buoyant tubular foils; and

first and second struts for connecting the first and second buoyanttubular foils to the command module, respectively;

wherein the first and second buoyant tubular foils provide substantiallyall of the buoyancy required for the marine vessel; and

wherein the marine vessel further comprises first and second enginesenclosed within the first and second buoyant tubular foils,respectively, and first and second propulsion units connected to thefirst and second engines, respectively, for moving the marine vesselthrough the water.

In another form of the present invention, there is provided a marinevessel comprising:

a command module;

first and second buoyant tubular foils; and

first and second struts for connecting the first and second buoyanttubular foils to the command module, respectively;

wherein the first and second buoyant tubular foils provide substantiallyall of the buoyancy required for the marine vessel; and

wherein the marine vessel further comprises first and second propellermechanisms mounted on the leading ends of the first and second buoyanttubular foils, respectively, for moving the marine vessel through thewater.

In another form of the present invention, there is provided a marinevessel comprising:

a command module;

first and second buoyant tubular foils; and

first and second struts for connecting the first and second buoyanttubular foils to the command module, respectively;

wherein the first and second buoyant tubular foils provide substantiallyall of the buoyancy required for the marine vessel; and

wherein the marine vessel further comprises a plurality of spoilersmounted on the first and second buoyant tubular foils for steering themarine vessel as it moves through the water.

In another form of the present invention, there is provided a marinevessel comprising:

a buoyant tubular foil; and

a propeller mechanism mounted on the leading end of the buoyant tubularfoil for moving the marine vessel through the water.

In another form of the present invention, there is provided a marinevessel comprising:

a buoyant tubular foil; and

a plurality of spoilers mounted on the buoyant tubular foil for steeringthe marine vessel as it moves through the water.

In another form of the present invention, there is provided a marinevessel comprising:

a buoyant tubular foil;

a propeller mechanism mounted on the leading end of the buoyant tubularfoil for moving the marine vessel through the water; and

a plurality of spoilers mounted on the buoyant tubular foil for steeringthe marine vessel through the water;

wherein each of the spoilers comprises a plate movable between (i) aninboard position wherein the plate is substantially aligned with theskin of the buoyant tubular foil to which the spoiler is mounted, and(ii) an outboard position wherein the plate projects into, and deflects,the water flowing by the buoyant tubular foil to which the spoiler ismounted.

In another form of the present invention, there is provided a method formoving through water, the method comprising:

providing a marine vessel comprising:

-   -   a command module;    -   first and second buoyant tubular foils; and    -   first and second struts for connecting the first and second        buoyant tubular foils to the command module, respectively;    -   wherein the first and second buoyant tubular foils provide        substantially all of the buoyancy required for the marine        vessel;    -   wherein the first and second struts are pivotally connected to        the command module and fixedly connected to the first and second        buoyant tubular foils, respectively; and    -   wherein the first and second struts comprise substantially rigid        planar structures; and

moving the marine vessel through water and adjusting the position of thefirst and second struts relative to the command module.

In another form of the present invention, there is provided a method formoving through water, the method comprising:

providing a marine vessel comprising:

-   -   a command module;    -   first and second buoyant tubular foils; and    -   first and second struts for connecting the first and second        buoyant tubular foils to the command module, respectively;    -   wherein the first and second buoyant tubular foils provide        substantially all of the buoyancy required for the marine        vessel; and    -   wherein the marine vessel further comprises first and second        engines enclosed within the first and second buoyant tubular        foils, respectively, and first and second propulsion units        connected to the first and second engines, respectively, for        moving the marine vessel through the water; and

moving the marine vessel through water.

In another form of the present invention, there is provided a method formoving through water, the method comprising:

providing a marine vessel comprising:

-   -   a command module;    -   first and second buoyant tubular foils; and    -   first and second struts for connecting the first and second        buoyant tubular foils to the command module, respectively;    -   wherein the first and second buoyant tubular foils provide        substantially all of the buoyancy required for the marine        vessel; and    -   wherein the marine vessel further comprises first and second        propeller mechanisms mounted on the leading ends of the first        and second buoyant tubular foils, respectively, for moving the        marine vessel through the water; and

moving the marine vessel through water.

In another form of the present invention, there is provided a method formoving through water, the method comprising:

providing a marine vessel comprising:

-   -   a command module;    -   first and second buoyant tubular foils; and    -   first and second struts for connecting the first and second        buoyant tubular foils to the command module, respectively;    -   wherein the first and second buoyant tubular foils provide        substantially all of the buoyancy required for the marine        vessel; and    -   wherein the marine vessel further comprises a plurality of        spoilers mounted on the first and second buoyant tubular foils        for steering the marine vessel as it moves through the water;        and

moving the marine vessel through water and adjusting the position of thespoilers.

In another form of the present invention, there is provided a method formoving through water, the method comprising:

providing a marine vessel comprising:

-   -   a buoyant tubular foil; and    -   a propeller mechanism mounted on the leading end of the buoyant        tubular foil for moving the marine vessel through the water; and

moving the marine vessel through water.

In another form of the present invention, there is provided a method formoving through water, the method comprising:

providing a marine vessel comprising:

-   -   a buoyant tubular foil; and    -   a plurality of spoilers mounted on the buoyant tubular foil for        steering the marine vessel as it moves through the water; and

moving the marine vessel through water and adjusting the position of thespoilers.

In another form of the present invention, there is provided a method formoving through water, the method comprising:

providing a marine vessel comprising:

-   -   a buoyant tubular foil;    -   a propeller mechanism mounted on the leading end of the buoyant        tubular foil for moving the marine vessel through the water; and    -   a plurality of spoilers mounted on the buoyant tubular foil for        steering the marine vessel through the water;

wherein each of the spoilers comprises a plate movable between (i) aninboard position wherein the plate is substantially aligned with theskin of the buoyant tubular foil to which the spoiler is mounted, and(ii) an outboard position wherein the plate projects into, and deflects,the water flowing by the buoyant tubular foil to which the spoiler ismounted; and

moving the marine vessel through water and adjusting the position of thespoilers.

In another form of the present invention, there is provided a marinevessel comprising:

an elongated closed underwater vehicle;

first and second propellers mounted on a forward end of said vehicle andadapted in operation to move said vehicle through water;

said first and second propellers comprising leading and trailingpropellers;

wherein said leading and trailing propellers are adapted to rotate inopposite directions to each other simultaneously;

whereby to provide propeller generated super-cavitated water flowingfrom the propellers and thence along an outer surface of said vehicle;

whereby to diminish friction on the outer surface of said vehicle andfacilitate high underwater speeds.

In another form of the present invention, there is provided a marinevessel comprising:

an elongated closed underwater vehicle;

propeller means mounted on a forward end of said vehicle;

said propeller means being operable to move said vehicle through waterand to produce super-cavitated water for flow aft of said propellermeans and adjacent an outer wall of said vehicle;

whereby to effect a water pressure on the vehicle outer wall less thanwater pressure forwardly of said propeller means.

In another form of the present invention, there is provided a marinevessel comprising:

a command module;

first and second buoyant tubular foils;

first and second struts connecting said first and second foils to saidcommand module;

wherein said first and second foils provide all buoyancy required forthe vessel;

wherein said struts are each pivotally connected to said command moduleand to one of said foils;

said first and second struts comprising generally rigid planarstructures; and

first and second propellers mounted on forward ends of said foils formoving the vessel through water;

wherein said first and second propellers comprise leading and trailingpropellers; and

wherein said leading and trailing propellers rotate in oppositedirections to create air skirts around the foils and extending alonglengths of the foils to decrease foil surface friction.

In another form of the present invention, there is provided a marinevessel comprising:

an elongated closed underwater vehicle;

a propeller mounted on a forward end of said vehicle and adapted inoperation to move said vehicle through water;

said propeller being of a size and configuration to provide propellergenerated super-cavitated water flowing from said propeller and thencealong an outer surface of said vehicle;

whereby to diminish friction on the outer surface of said vehicle andfacilitate high underwater speeds.

In another form of the present invention, there is provided a method formoving through water, the method comprising:

providing a marine vessel comprising:

-   -   a command module;    -   first and second buoyant tubular foils; and    -   first and second struts for connecting the first and second        buoyant tubular foils to the command module, respectively;    -   wherein the first and second buoyant tubular foils provide        substantially all buoyancy required for the marine vessel; and    -   wherein the marine vessel further comprises first and second        propeller mechanisms mounted on the forward ends of the first        and second buoyant tubular foils, respectively, for moving the        marine vessel through water; and

moving the marine vessel through water.

In another form of the present invention, there is provided a method formoving through water, the method comprising:

providing a marine vessel comprising:

-   -   a buoyant tubular foil; and    -   a propeller mechanism mounted on the forward end of the buoyant        tubular foil for moving the marine vessel through the water; and

moving the marine vessel through water.

In another form of the present invention, there is provided a method formoving through water, the method comprising:

providing a marine vessel comprising:

-   -   a buoyant tubular foil;    -   a propeller mechanism mounted on the forward end of the buoyant        tubular foil for moving the marine vessel through water; and    -   a plurality of spoilers mounted on the buoyant tubular foil for        steering the marine vessel through water;    -   wherein each of the spoilers comprises a plate movable        between (i) an inboard position wherein the plate is        substantially aligned with a skin of the buoyant tubular foil to        which the spoiler is mounted, and (ii) an outboard position        wherein the plate projects into, and deflects, water flowing by        the buoyant tubular foil to which the spoiler is mounted; and

moving the marine vessel through water and adjusting the positions ofthe spoilers.

In another form of the present invention, there is provided an elongatedtubular foil for travel through water, the foil being provided with apropulsion means;

said propulsion means comprising in part a propeller means rotatablymounted on a forward end of the foil and adapted to move the foilthrough the water;

said propeller means being adapted to effect supercavitation of waterwhile operative to move the foil through the water;

to thereby create a skirt of supercavitated water adjacent at least aportion of an outer skin of the foil;

such that the foil moves through the skirt of supercavitated water.

In another form of the present invention, there is provided a method forpropelling a body through water, the method comprising the steps of:

providing the body in an elongated tubular configuration having apropulsion means rotatably mounted on a forward end of the body andadapted to move the body through the water;

activating the propulsion means so as to effect the movement of the bodythrough the water and so as to create a skirt of supercavitated wateradjacent at least a portion of an outer skin of the body;

such that the body moves through the supercavitated water adjacentthereto.

In another form of the present invention, there is provided an elongatedtubular body for travel through water, the elongated tubular body beingprovided with a propulsion means;

said propulsion means comprising in part a propeller means rotatablymounted on a forward end of the elongated tubular body and adapted tomove the elongated tubular body through the water;

said propeller means being adapted to effect supercavitation of waterwhile operative to move the elongated tubular body through the water tothereby create a skirt of supercavitated water adjacent at least aportion of an outer skin of the elongated tubular body;

such that the elongated tubular body moves through the skirt ofsupercavitated water with substantially reduced hull friction.

In another form of the present invention, there is provided a method forpropelling a body through water, the method comprising the steps of:

providing the body in an elongated tubular configuration having apropulsion means rotatably mounted on a forward end of the body andadapted to move the body through the water;

activating the propulsion means so as to effect the movement of the bodythrough the water and so as to create a skirt of supercavitated wateradjacent at least a portion of an outer skin of the body;

such that the body moves through the supercavitated water adjacentthereto with substantially reduced hull friction.

In another form of the present invention, there is provided asubmersible vessel comprising:

an elongated hull;

at least one propeller mounted on a forward end of said hull and adaptedto move said hull through water;

said at least one propeller being of a size and configuration such thatwhen it is rotated at an appropriate speed, it generates supercavitatedwater flowing from said at least one propeller and thence along an outersurface of said hull so as to diminish friction on the outer surface ofsaid hull and facilitate high underwater speeds.

In another form of the present invention, there is provided a method formoving through water, the method comprising:

providing a submersible vessel comprising:

-   -   an elongated hull;    -   at least one propeller mounted on a forward end of said hull and        adapted to move said hull through water;    -   said at least one propeller being of a size and configuration        such that when it is rotated at an appropriate speed, it        generates supercavitated water flowing from said at least one        propeller and thence along an outer surface of said hull so as        to diminish friction on the outer surface of said hull and        facilitate high underwater speeds;

submerging at least a portion of the elongated hull; and

rotating the at least one propeller so as to move the submersible vesselthrough water.

In another form of the present invention, there is provided a marinevessel comprising:

at least one buoyant tubular foil; and

at least one baffle plate positioned about the perimeter of the at leastone buoyant tubular foil so as to protrude into the flow of waterpassing by the perimeter of the at least one buoyant tubular foil,whereby to create a high-pressure zone fore of the at least one baffleplate and a low-pressure zone immediately aft of the at least one baffleplate, whereby to create a dense stream of supercavitated waterimmediately aft of the at least one baffle plate.

In another form of the present invention, there is provided a method formoving through water, the method comprising:

providing a marine vessel comprising:

-   -   at least one buoyant tubular foil; and    -   at least one baffle plate positioned about the perimeter of the        at least one buoyant tubular foil so as to protrude into the        flow of water passing by the perimeter of the at least one        buoyant tubular foil, whereby to create a high-pressure zone        fore of the at least one baffle plate and a low-pressure zone        immediately aft of the at least one baffle plate, whereby to        create a dense stream of supercavitated water immediately aft of        the at least one baffle plate; and

moving the marine vessel through water, such that the passage of waterpast the at least one baffle plate creates a high-pressure zone fore ofthe at least one baffle plate and a low-pressure zone immediately aft ofthe at least one baffle plate, whereby to create a dense stream ofsupercavitated water immediately aft of the at least one baffle plate.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and features of the present invention will bemore fully disclosed or rendered obvious by the following detaileddescription of the preferred embodiments of the invention, which is tobe considered together with the accompanying drawings wherein likenumbers refer to like parts and further wherein:

FIG. 1 is a schematic view showing a novel fleet protection attack craftformed in accordance with the present invention;

FIGS. 2-9 are schematic views showing further construction details ofthe novel attack craft shown in FIG. 1, including further details of itscommand module, buoyant tubular foils (BTFs) and struts;

FIGS. 10-15 are schematic views showing further details of the BTFs andstruts, and the internal components thereof;

FIGS. 15A and 15B are schematic views showing how a gaseous envelope maybe provided around the BTFs so as to reduce drag as the vessel movesthrough the water;

FIGS. 15C-15F are schematic views showing a venturi injection ringdisposed adjacent to the perimeter of a BTF for producing anencompassing gaseous envelope about the BTF;

FIGS. 15G-15W are schematic views showing one or more baffle platesprovided about the periphery of a BTF for producing an encompassinggaseous envelope about the BTF;

FIGS. 15X-15Z and 15ZA-15ZD are schematic views showing a baffle platewith means for injecting air (or another fluid) from the trailingsurface of the baffle plate;

FIG. 15ZE is a schematic view showing steam generated by hot engineexhaust being ejected from openings in the BTF so as to create anencompassing gaseous envelope about the perimeter of the BTF;

FIGS. 16-26 are schematic views showing further details of the spoilersused to steer the novel attack craft and adjust its attitude;

FIGS. 27-36 are schematic views showing how the position of the strutsand BTFs can be adjusted relative to the command module;

FIG. 37 is a cross-sectional view of a buoyant tubular foil (BTF) havingair trap fins disposed on some or all of its periphery, and furthershows preferred configurations for the air trap fins—in addition, thisview shows a plurality of air outlet holes formed in the hull of thebuoyant tubular foil;

FIG. 37A is a view similar to that of FIG. 37, but showing asubstantially complete array of air trap fins mounted on the outer hullof the buoyant tubular foil (BTF);

FIGS. 37B and 37C are side elevational views of a buoyant tubular foil(BTF) and a strut supporting the buoyant tubular foil, wherein thebuoyant tubular foil comprises air trap fins on its periphery, andfurther wherein the buoyant tubular foil and the supporting strut have aplurality of air outlet holes formed therein;

FIG. 37D is a cross-sectional view of a buoyant tubular foil (BTF)having air outlet holes formed therein;

FIG. 37E is a schematic view of a buoyant tubular foil (BTF) having asingle front propeller mechanism for generating a supercavitated aircurtain (e.g., an envelope or skirt of gaseous bubbles) encompassing thehull of the buoyant tubular foil;

FIG. 38 is a schematic view of a submarine comprising a buoyant tubularfoil (i.e., a tubular hull) equipped with a front pulling propellermechanism for generating a supercavitated air curtain (e.g., an envelopeor skirt of gaseous bubbles) encompassing the hull of submarine;

FIGS. 38A, 38B, 38C and 38D are schematic views of a novel submarineformed in accordance with the present invention;

FIG. 39 is a schematic view of a torpedo comprising a buoyant tubularfoil (i.e., a tubular hull) equipped with a front pulling propellermechanism for generating a supercavitated air curtain (e.g., an envelopeor skirt of gaseous bubbles) encompassing the hull of torpedo;

FIG. 40 is a schematic view of a novel unmanned submersible craft formedin accordance with the present invention; and

FIG. 41 is a schematic view showing one manner of using the novelunmanned submersible craft shown in FIG. 40.

DETAILED DESCRIPTION OF THE INVENTION Overview

Looking first at FIGS. 1-6, there is shown a novel fleet protectionattack craft 5. Attack craft 5 generally comprises a command module 100for carrying a crew, weapons and payload (including passengers), a pairof buoyant tubular foils (BTFs) 200 for providing buoyancy, propulsionand steering, and a pair of struts 300 for supporting command module 100on BTFs 200.

As seen in FIGS. 4, 7 and 8, and as will hereinafter be discussed infurther detail, struts 300 can be disposed in a variety of differentpositions vis-à-vis command module 100, so that attack craft 5 canassume a number of different configurations, depending on the desiredmode of operation, whereby to provide high speed, extreme stability andstealth capability.

Thus, for example, in standard seas, attack craft 5 may be placed in theconfiguration shown in FIG. 4 (i.e., so that struts 300 are disposedapproximately 45 degrees off the horizon, and at approximately a rightangle to one another) so that command module 100 is safely out of thewater and the vessel has modest radar, infrared and visual signatures.

However, in high seas, while operating at high speed, attack craft 5 maybe placed in the configuration shown in FIG. 7 (i.e., so that struts 300are disposed substantially perpendicular to the horizon, andsubstantially parallel to one another) so that command module 100 standswell out of the water and is free from the affect of swells.

Furthermore, depending on sea conditions, attack craft 5 may be placedin a configuration somewhere between those shown in FIGS. 4 and 7.

Attack craft 5 is also designed to operate in stealth mode, by loweringits physical profile. In this case, attack craft 5 may be placed in theconfiguration shown in FIG. 8 (i.e., so that struts 300 are disposedalmost parallel to the horizon, and almost co-linear with one another)so that command module 100 is disposed just above, or actually in, thewater, reducing its radar, infrared and visual signatures. This mode canbe very useful when attack craft 5 is being used for reconnaissancepurposes and/or to deliver small teams of special forces behind enemylines and/or to extract the same.

Thus, in one preferred form of the invention, attack craft 5 is normallyoperated in the configuration shown in FIG. 4, with command module 100completely out of the water, but the command module being as low aspossible so as to have a reduced profile. However, in high seas and athigh speed, attack craft 5 may be operated in the configuration shown inFIG. 7, so that command module 100 stands well clear of any swells. And,when desired, attack craft 5 may be operated in the configuration shownin FIG. 8 so as to assume a stealth mode.

Or, attack craft 5 may be operated in a selected configuration somewherebetween those shown in FIGS. 4, 7 and 8.

Prior Art Designs for Achieving High Speed and/or Extreme Stability

There are currently two competing approaches for achieving high speedand/or high stability in a water craft. These are (i) the hydrofoilapproach, which generally provides high speed; and (ii) the SmallWaterplane Area Twin Hull (SWATH) approach, which generally provideshigh stability.

The Hydrofoil Approach

Hydrofoils have been in experimental use for many years, and today arein active service around the world for a variety of applications.Hydrofoils generally employ small airplane-like wings (“lifting foils”)which provide lift for the hull of the vessel. These lifting foils aretypically lowered into the water while the vessel is underway. At higherspeeds, the lifting foils are capable of lifting the hull of the vesselcompletely out of the water, thereby allowing the vessel to operate withonly its lifting foils (and their supporting struts) in the water,whereby to minimize drag and increase vessel speed. However, the liftingfoils themselves provide no buoyancy and therefore cannot support thevessel at slower speeds. Thus, the vessel can only operate in hydrofoilmode when moving at substantial speeds. In addition, due to the thinnature of the hyrdofoil's lifting foils, it is not possible to house thevessel's engines within the lifting foils themselves—instead, it isnecessary to house the engines within the hull of the vessel and to usetransmission technologies (e.g., mechanical, hydraulic and/or electricalmeans) to transfer power from the vessel's engines down to its liftingfoils, which carry the propellers. However, these power transmissiontechnologies all involve substantial losses in power (therebynecessitating the use of larger engines and/or resulting in lowerspeeds) and significantly complicate the propulsion system of thevessel.

The SWATH Approach

SWATH vessels employ two or more torpedo-shaped structures which aredisposed underwater and attached to the main body of the vessel withfixed vertical struts. The torpedo-shaped structures provide buoyancyfor the main body of the vessel, which remains completely out of thewater. In this way, SWATH vessels resemble catamarans, except that thetwo pontoon hulls of the catamaran are replaced by underwatertorpedo-shaped structures which reside immediately below the hull at theends of the vertical struts. The SWATH design generally providesexcellent stability because the underwater torpedo-shaped structures areless affected by wave action than a traditional wave-riding hull.However, the substantial skin friction, and the inefficient hydromanticshape, of the large underwater torpedo-shaped structures generallyresult in higher power consumption. This higher power consumption inturn necessitates the use of larger engines and/or results in reducedvessel speed. However, the use of larger engines is itself problematic,since the engines must then be housed in the hull or, if the engines areto be housed in the underwater torpedo-shaped structures, the underwatertorpedo-shaped structures must be enlarged. Housing the engines in thehull introduces all of the power transmission problems discussed abovewith respect to hydrofoils, inasmuch as the propellers are mounted tothe underwater torpedo-shaped structures. Conversely, enlarging theunderwater torpedo-shaped structures increases the skin frictionproblems, and the inefficient hydromantic shape problems, discussedabove—which in turn necessitates the use of even larger engines. Forthis reason, it has previously been impossible to build a small,high-speed SWATH vessel. In addition to the foregoing, the SWATH designtypically requires a high profile in order to ensure that the hull ofthe vessel remains completely out of water, particularly in high seas.This gives the SWATH vessel larger radar, infrared and visualsignatures, thereby making it easy to detect and target.

Novel Approach for Achieving High Speed and Extreme Stability

The present invention overcomes the problems associated with the priorart through the provision and use of novel fleet protection attack craft5. Attack craft 5 supports its command module 100 on a pair of buoyanttubular foils (BTFs) 200 via movable struts 300. BTFs 200 normallyprovide all of the buoyancy required for the craft, with command module100 remaining completely out of the water. More particularly, BTFs 200and struts 300 are often the only portions of the craft which contactthe water, and they provide low friction hydromantic cross-sections soas to minimize water resistance. Significantly, BTFs 200 housesubstantially all of the propulsion, fuel and steering systems for thecraft, thereby providing the craft with an unusually low center ofgravity and permitting the volume of command module 100 to be dedicatedto crew, weapons and payload. Furthermore, struts 300 are movablerelative to command module 100, thereby permitting the craft to assume anumber of different configurations. This unique approach results in acraft with unparalleled speed and stability regardless of seaconditions, and with lower radar, infrared and visual signatures,thereby making it difficult to detect and target. Various aspects of thecraft will now be discussed in further detail.

Command Module 100

Looking now at FIGS. 1-9, command module 100 generally comprises awatertight enclosure 105 (FIG. 3) having a hull-like bottom surface 110(FIGS. 4, 5, 7 and 8). Command module 100 includes a cockpit 115 (FIGS.2, 3, 6 and 8) for housing a pilot and weapons officer, and a bay 120(FIG. 9) for housing weapons and payload (including passengers). Commandmodule 100 further includes a rear hatch 125 (FIGS. 5, 6 and 9) forpermitting entry and exit of crew, weapons and payload (includingpassengers), and a top hatch 130 (FIGS. 2, 6 and 9) for permittingvarious weapons systems to be raised out of bay 120, fired, and thenlowered back into bay 120.

Command module 100 is armored to protect all occupants, weaponry andpayload. Windscreens 135 (FIGS. 7 and 9) are formed out ofbullet-resistant materials.

Command module 100 comprises watertight bulkhead enclosures which,combined with hull-like bottom surface 110, allow waves to wash over thecommand module without effect when attack craft 5 is operating in itsstealth mode (see below). Automatic vent doors seal any open systemsagainst water leakage when attack craft 5 is in this stealth mode.

The outer structure of command module 100 is preferably based onso-called “stealth” principals in order to minimize the radar signatureof the craft. More particularly, the outer surface of command module 100is designed to deflect radar energy and return only a minimal amount ofradar energy to the radar transmitter. To this end, the exteriorsurfaces of command module 100 are preferably highly angular, with theangles being selected so as to reflect the radar energy either downwardtowards the water or upward into the sky. In any case the exteriorsurfaces of command module 100 minimize the amount of radar energyreflected directly back to the sender. Furthermore, command module 100preferably incorporates a radar-absorbent paint which is capable ofabsorbing or further reducing any incident radar energy.

Command module 100 is also configured to house all of the controlsystems for piloting the attack craft, all of the weapons controlsystems for operating the weapons carried by the attack craft, anauxiliary generator for supplemental power requirements (e.g., fornavigation), a battery charger, an air filtration system, a head, asink, an air compressor, etc.

The weapons systems carried by attack craft 5 preferably comprise (i)one 20 mm Vulcan Gatling gun, equipped with optic and night vision; (ii)two 30 caliber Miniguns equipped with optic and night vision; (iii) oneor more 2.5 inch laser-guided rockets; and (iv) 8 “mini” torpedoes.Preferably the Gatling gun, Miniguns and rockets are housed within bay120 for elevated deployment through top hatch 130, and the “mini”torpedoes are mounted to the exterior of command module 100, e.g., suchas is shown at 140.

Buoyant Tubular Foils (BTFs) 200

Looking next at FIGS. 10-15, a pair of buoyant tubular foils (BTFs) 200provide buoyancy, propulsion and steering for attack craft 5. Each ofthe BTFs 200 generally comprises a hollow tubular structure 205 whichhouses an engine 210 for powering a propeller system 215, a fuel tank220 for supplying fuel to engine 210, and steering elements (orspoilers) 225 for steering attack craft 5.

Hollow Tubular Structure 205

Hollow tubular structure 205 generally comprises a hollow hull whichprovides buoyancy for attack craft 5. Hollow tubular structure 205 isconfigured so as to provide stability at low speed operations whilestill providing low water friction and an improved hydromantic profileso as to enable speeds of over eighty (80) knots. At high speeds, theconfiguration of hollow tubular structure 205 provides extraordinarystability for the vessel, due to the flow of water over the elongatedtubular structure.

More particularly, the low friction hydromantic cross-section of hollowtubular structure 205 traverses water with the lowest possible skinfriction forces and the best hydromantic shape obtainable, yet stillhouses engine 210 and fuel tank 220, and supports propeller system 215and steering elements 225. It has been determined that best performanceis achieved where hollow tubular structure 205 has a cross-section whichis between about 1/10 and about 1/30 of the length of hollow tubularstructure 205, and preferably about 1/20 of the length of the hollowtubular structure. By way of example but not limitation, excellentperformance can be achieved when the hollow tubular structure 205 has a3 foot outer diameter and a 60 foot length.

As seen in FIGS. 12-15, hollow tubular structure 205 comprises aplurality of disconnectable sections that permit easy access tocomponents disposed within the interior of hollow tubular structure 205,e.g., for maintenance and quick replacement of power and sensor modules.By way of example but not limitation, hollow tubular structure 205 cancomprise a center section 230 which is mounted to a strut 300, a forwardsection 235 which is dismountable from center section 230, and a rearsection 240 which is dismountable from center section 230. Preferably,interior components are equipped with slides for easy entry into, andremoval from, hollow tubular structure 205. By way of example but notlimitation, FIG. 14 shows how engine 210 may be equipped with slides 245for supporting engine 210 within hollow tubular section 205, and tofacilitate insertion into, and removal from, hollow tubular structure205.

Forward section 235 and rear section 240 can mount to center section 230in a variety of ways. By way of example but not limitation, the sectionscan be mechanically held together (e.g., by hydraulics, power screwactions, etc.) or they can twist lock together (e.g., in the manner of abayonet-type mount). A watertight seal is provided between the sectionsso as to ensure hull integrity. The seal can be a continuous circularshape to match the cross-section of hollow tubular structure 205, e.g.,a resilient O-ring having a round or flat cross-section. Alternatively,the O-ring can be an inflatable seal (e.g., like the inner tube of abicycle tire) that can provide adjustable sealing forces by theinjection of an appropriate amount of fluid (e.g., gas or liquid).Preferably, each O-ring seal has two sealing surfaces, i.e., the facesurface between adjacent sections and the face surface against the skinof hollow tubular structure 205.

The ability to quickly unlock the various sections of hollow tubularstructure 205 permits the rapid servicing and/or replacement of thevarious components contained within hollow tubular structure 205, e.g.,engine 210, fuel tank 220, etc.

Gas Turbine (Jet) Engine Propulsion

Engine 210 can be a conventional diesel engine, internal combustionengine, rotary engine, electric motor, etc. Preferably, however, engine210 comprises a gas turbine (jet) engine, e.g., of the sort used inaircraft, and particularly of the sort used in helicopters. A gasturbine engine is preferred due to its high power, small size and lowweight. More particularly, a gas turbine engine typically has ahorsepower-to-weight ratio of about 2.5 horsepower (HP) per pound. Bycomparison, a modern marine diesel engine typically has ahorsepower-to-weight ratio of about 0.5 HP per pound. Inasmuch as thereis generally a direct correlation between vessel acceleration andweight, it is generally desirable to use a high power, low weight enginein a high speed craft. Thus, a gas turbine engine is the preferredpropulsion unit for attack craft 5.

Significantly, a gas turbine engine is also ideal for use in attackcraft 5 inasmuch as its size and configuration are perfectly suited fordisposition within hollow tubular structure 205. More particularly, gasturbine engines typically have an elongated, somewhat cylindricalconfiguration which easily fits within a hollow tubular structure.Significantly, gas turbine engines generally have relatively modestcross-sections, such that the gas turbine engines can fit within arelatively small diameter tube. By way of example but not limitation,the T53L13 gas turbine (jet) engine manufactured by Lycoming Engines (adivision of Avco Corporation, a wholly owned subsidiary of Textron,Inc.) of Williamsport, Pa. has a diameter which is ideally suited fordisposition within hollow tubular structure 205 of attack craft 5.

The use of a gas turbine engine in BTFs 200 also provides significantadditional advantages.

First, the use of a gas turbine engine in each BTF 200 easily allows forthe use of a centerline drive shaft to transfer power to propellersystem 215. This is an enormous advantage when it comes to efficientlydelivering large amounts of power to propeller system 215.

Second, the gas turbine engine provides a starter generator thatperforms two functions, i.e., (i) to start the turbine engine, and (ii)to generate DC power. More particularly, most gas turbine enginesprovide 24 volts DC at 300 amps. This allows attack craft 5 to power allof its electrical systems from the gas turbine engines, with the needfor only a small supplemental generator for charging batteries.

In addition, placing a gas turbine engine inside hollow tubularstructure 205, which is always underwater, also provides superiorcooling for the gas turbine engine since the radiated engine heat istransferred to the surrounding water through the skin of hollow tubularstructure 205.

Furthermore, gas turbine engines are generally designed to be quicklyand easily removed (e.g., by sliding) from an aircraft fuselage.Similarly, the gas turbine engine can be quickly and easily removed(e.g., by sliding) from hollow tubular structure 205.

The gas turbine engine usually has a high internal rpm (greater than19,000 rpm) with internal gear reductions. Preferably, a gearbox 250using planetary gears connects engine 210 to propeller system 215. Thisapproach provides a gearbox which is smaller than the outside diameterof the gas turbine engine.

Gas Turbine (Jet) Engine Intake and Exhaust

The “Achilles heel” of a gas turbine engine is its need to rapidlyintake large quantities of fresh air and to rapidly expel largequantities of exhaust air. As a result of this need to rapidly movelarge quantities of air in and out of the gas turbine engine, gasturbine engines have not heretofore been a candidate for use inunderwater structures (e.g., submarines and the submerged portions ofSWATH vessels) due to the inability to adequately aspirate the jetengines.

A critical aspect of attack craft 5 is the air intake and exhaustsystems which support the use of gas turbine engines underwater. In thisrespect it will be appreciated that the design of the air intake andexhaust systems is complicated by the fact that attack craft 5 isdesigned to change configurations (e.g., as shown in FIGS. 4, 7 and 8)and the air intake and exhaust systems must be able to accommodate theseconfiguration changes. More particularly, in attack craft 5, the gasturbine engines are housed underwater in BTFs 200, the BTFs 200 aredisposed at the ends of struts 300, and struts 300 are movable relativeto command module 100 (see FIGS. 4, 7 and 8). Thus, the air intake andexhaust systems of attack craft 5 must be capable of rapidly movinglarge quantities of air in and out of the gas turbine engines, andthrough struts 300, while at the same time accommodating movement ofstruts 300 relative to command module 100.

To this end, attack craft 5 comprises an air intake and exhaust systemfor rapidly delivering large quantities of fresh air to gas turbineengine 210 and for rapidly expelling large quantities of exhaust airfrom gas turbine engine 210. The air intake and exhaust system generallycomprises an engine intake duct 255 and an engine exhaust duct 260. Theintake side of engine intake duct 255 is disposed in command module 100so that it can access cool air, which increases the efficiency of gasturbine engines 210. Preferably, the intake side of engine intake duct255 is funneled so as to generate ram air forces while attack craft 5 ismoving at speed, which further increases the efficiency of gas turbineengines 210. The outlet side of engine exhaust duct 260 is disposed incommand module 100 so as to provide efficient exhaust venting with aminimal heat signature. Engine intake duct 255 and engine exhaust duct260 preferably pass through a flexible coupling located at the junctionof the strut and the command module, in order to accommodate movement ofthe strut vis-à-vis the command module. This flexible coupling alsoaccommodates other lines passing from command module 100 to BTFs 200 viastruts 300, e.g., fuel re-fill lines, electrical power lines, electricalcontrol lines, etc.

It should be appreciated that the flexible coupling is configured so asto allow engine intake and engine exhaust to be vectored and bent whilestill accommodating the large gas volumes associated with the gasturbine engine. Furthermore, the flexible coupling is designed toaccommodate the high exhaust temperatures created by the gas turbineengine. The use of heat-resistant flexible materials in the coupling isessential to allow movement of the struts relative to the commandmodule.

It should also be appreciated that moving large quantities of airthrough a narrow strut (which is thinner than BTF 200) entails usingsubstantially the entire inner structure of the strut as an air intakeduct and an engine exhaust duct. In one preferred form of the invention,engine exhaust duct 260 is routed inside air intake duct 255 so as toallow the exhaust to be cooled by the intake air, whereby to provide alower thermal signature for attack craft 5. In another preferred form ofthe invention, engine exhaust duct 260 is not routed inside air intakeduct 255—rather, in this form of the invention, engine exhaust duct 260is separate from air intake duct 255, and the exhaust in engine exhaustduct 260 is separately cooled, e.g., with a water cooling jacket.Furthermore, in this form of the invention, insulation may be used tokeep the cool air in air intake duct 255 from being heated by the hotexhaust in engine exhaust duct 260 in order to increase the efficiencyof gas turbine engines 210.

Preferably, engine exhaust duct 260 includes insulation to prevent theheat of gas turbine engine 210 from overheating the outer skin of strut300.

In one form of the present invention, engine exhaust ducts 260 aredouble-walled, so as to allow a fluid to be circulated around the innerhot duct, whereby to further cool the engine exhaust and provide a lowerthermal signature.

Attack Craft Propulsion Using Battery Power

Preferably, attack craft 5 also includes an electric motor (not shown)and batteries (not shown) for selectively driving propeller system 215.More particularly, in certain circumstances (e.g., reconnaissanceoperations and the delivery and/or extraction of special forces) it maybe desirable to operate with reduced noise. In these circumstances, theelectric motor and batteries may be used in place of the gas turbine(jet) engine discussed above.

Propeller System 215

Most vessels in use today utilize propellers which are disposed at thestern of the vessel and push the vessel through the water. This approachis generally satisfactory for most vessels. However, stern-mounted,pushing propellers are generally not satisfactory for those vesselswhich are trying to achieve very high speeds, e.g., speeds in excess of80 knots. This is because propellers located at the stern of the vesselengage water which has been agitated by the prior passage of the vesselthrough the water. Since the efficiency of propellers is highly affectedby the state of the water the propellers move through, stern-mounted,pushing propellers are generally impractical for high speed craft.

Some high speed boats in use today (e.g., hydroplanes and ocean racingboats) use stern-mounted, surface-penetrating, forward-facing propellersthat ride partially submerged in agitated water with air mixed in. Thesepiercing propellers are designed with a heavy trailing edge andanti-cavitation cupping. These piercing propellers withstand the extremeforces of high horsepower and high rpm because the propeller is neverfully engaged in the water.

However, this type of propeller would not be effective for attack craft5, since with BTF 200, propeller system 215 must be fully submerged.

Significantly, the present invention utilizes a propeller system 215which comprises a pair of forward-facing, pulling, counter-rotatingpropellers 265, 270 located at the bow end of each BTF 200.

More particularly, a propeller system 215 is placed at the bow of eachBTF 200 so that the forward-facing, pulling propellers can “bite” intovirgin, undisturbed water, whereby to obtain maximum efficiency.Furthermore, each propeller system 215 comprises two propellers, aleading propeller 265 and a trailing propeller 270, operated in a timed,counter-rotating mode, so as to provide reduced cavitation for theforward propeller. Leading propeller 265 is the main propulsion elementand does the majority of the work of pulling of the vessel. Trailingpropeller 270 spins in the opposite direction from the leading propellerand evacuates water from behind the leading propeller, therebypermitting the leading propeller to work with maximum efficiency. Thus,trailing propeller 270 moves water out from behind leading propeller 265so that the leading propeller can pull more water in. This providesincreased propeller efficiency, which translates into higher speed andlower fuel consumption.

Using serially-mounted, counter-rotating propellers 265, 270 alsopermits smaller propeller diameters to be used. This is because thesurface areas of the two propellers combine so as to provide an overalleffective surface area which is equivalent to the surface area of asingle, larger diameter propeller. However, it is difficult to rotate alarge diameter propeller at high speeds due to the forces involved.Thus, the use of serially-mounted, counter-rotating propellers permitsthe propellers to be rotated at higher rpms, thereby permitting higherspeeds to be achieved.

In addition to the foregoing, by using two counter-rotating propellers,there is no side torque. More particularly, side torque in propellers isthe result of the centrifugal forces created by the rotation of thepropeller. This side torque creates a tendency for the vessel to turn inthe direction of the rotation of the blade. Side torque is not desiredwith attack craft 5, since it involves a loss of energy and can createsteering issues for the vessel.

A gearbox 250 connects a gas turbine engine 210 to a propeller system215. More particularly, gearbox 250 is configured to convert the singlerotational motion of the output shaft of a gas turbine engine 250 intothe dual, co-axial, counter-rotational motions needed to drive thecounter-rotating propellers, 265, 270.

Super-Cavitation

By placing the counter-rotating propellers 265, 270 on the forward endof BTFs 200, the propellers are able to pull the vessel through clean,undisturbed, virgin water, thereby ensuring optimal propellerperformance. In addition, by placing the two serially-mounted,counter-rotating propellers on the front end of BTFs 200, attack craft 5is able to generate a highly gaseous environment, comprising a jetstream of dense collapsing bubbles, that encapsulate BTFs 200 andsignificantly reduce vessel drag. More particularly, the actions ofpropellers 265, 270, working together, pull water through the leadingpropeller 265 and allow the trailing propeller 270 to heavily cavitatethe rapidly moving water and create a heavy stream of gaseous bubbleswhich surround the outer surfaces of BTFs 200. This encompassing gaseousenvelope (which is sometimes hereinafter referred to as a supercavitatedair curtain, an envelope or skirt of gaseous bubbles, supercavitatedwater, and the like, all of which are intended to mean a highly gaseousenvironment of bubbles, and/or a single bubble that fully encases asubmerged body) reduces hull drag and greatly increases the speed of thevessel, since the BTFs are essentially “flying through bubbles”. SeeFIG. 15A. In this respect it should be appreciated that the kineticcoefficient of friction with air is approximately 1/800th the kineticcoefficient of friction of water. Furthermore, the faster the vesselgoes, the greater the reduction in hull friction, inasmuch as (i) agreater quantity of gaseous bubbles are created by the serially-mounted,counter-rotating propellers, and (ii) the bubbles do not have time tocollapse before BTFs 200 have passed completely through them.

Additional Means for Producing an Encompassing Gaseous Envelope

Attack craft 5 can also include additional means for producing anencompassing gaseous envelope about BTFs 200, whereby to reduce hullfriction and thereby increase the speed of the vessel.

More particularly, in one form of the invention, a plurality of smallopenings 275 (FIG. 15B) are preferably located immediately aft oftrailing propeller 270 and disposed in a circular fashion about some orall of the periphery of the BTF structure. These small openings 275 arein communication with ductwork or tubing leading to the outside air,allowing the flowing water coming off the trailing propeller 270 tocreate a siphon effect, drawing air down for release just aft of thetrailing propeller, whereby to create an even more dense gaseousenvelope for reducing BTF friction.

In one preferred form of the invention, and looking now at FIGS. 15C,15D and 15E, at least one venturi injection ring 276 is positioned aboutsome or all of the circumference of BTF 200, spaced slightly from theoutside surface 278 of the BTF. In one preferred form of the invention,one venturi injection ring 276 is disposed just aft of trailingpropeller 270 and extends about the entire circumference of BTF 200.Venturi injection ring 276 comprises an inner profile 277 which isconfigured to cooperate with the outer profile 278 of the adjacentperipheral portion 279 of BTF 200 so as to create a large opening 280,followed by a small opening 281, followed by a large opening 282,whereby to create a so-called “venturi effect” for the water flowingbetween venturi injection ring 276 and the adjacent outer profile 278 ofperipheral portion 279 of BTF 200. This venturi effect causes the waterflowing between venturi injection ring 276 and the adjacent outerprofile 278 of peripheral portion 279 of BTF 200 to be accelerated,whereby to induce a pressure drop at venturi injection ring 276 aft ofsmall opening 281. This pressure drop draws air (or another gas) out ofone or more supply tubes 283, which extend between a plurality of smallopenings 275 (which may be bores or grooves) and an air source (such asthe ambient air outside command module 100, obtained via an air intakedisposed at the command module or a strut or via a snorkel extendingupward from the BTF) or another gas source, whereby to provide a gaseousenvelope aft of venturi injection ring 276. This gaseous envelopeencompasses BTF 200 and thereby reduces hull drag and greatly increasesthe speed of the vessel. Note that the gaseous envelope created byventuri injection ring 276 supplements and enhances the gaseous envelopeproduced by the two serially-mounted, counter-rotating propellers on thefront end of BTFs 200, thereby providing even more reduction of hulldrag and further increasing the speed of the vessel.

It should also be appreciated that, if desired, venturi injection ring276 can be used to draw other gases or liquids (instead of, or inaddition to, ambient air) through supply tubes 283 and out of smallopenings 275, whereby to modify or enhance the gaseous envelope whichencompasses BTF 200. By way of example but not limitation, such othergases or liquids may comprise polymers, soaps, oils, etc.

See FIG. 15F, which shows, in schematic form, the construction andfunction of venturi injection ring 276 in greater detail.

If desired, multiple injection rings 276 may be provided on a BTF 200.

If desired, venturi injection ring 276 can have a variable configurationsuch that the dimensions of large opening 280, small opening 281 and/orlarge opening 282 can be selectively changed, whereby to modify theventuri effect provided by venturi injection ring 276. This variableconfiguration can be implemented by mechanical and/or inflatableelements disposed on or forming venturi injection ring 276.

As will hereinafter be discussed, BTF 200 may also be used as the hullof a submarine, or as the hull of a torpedo, or as the hull of anunmanned drone, etc. In this respect it should be appreciated thatventuri injection ring 276 may also be utilized on these craft so as toreduce hull drag and increase the speed of the craft.

Furthermore, it should be noted that, if desired, venturi injection ring276 may be used on submerged surfaces of substantially any water craft,including water craft using rear propulsion means such as rearpropellers, rear water jets, etc., so as to reduce hull drag andincrease the speed of the craft. By way of example but not limitation,venturi injection ring 276 may be used on a rear propulsion SWATHvessel, a rear propulsion submarine, a rear propulsion torpedo, a rearpropulsion unmanned drone, etc.

And, if desired, venturi injection ring 276 can be movable relative toBTF 200 such that venturi injection ring 276 can be disposed flush withthe outer surface of BTF 200 and then deployed outwardly of BTF 200 whenthe venturi effect is desired. This construction can be highlyadvantageous in certain circumstances, e.g., where the venturi injectionring 276 is to be provided on a torpedo which must be launched from atorpedo tube.

In another form of the present invention, a pressurized gas source,connected to small openings 275, can also be used to release gas (and/orliquids) immediately aft of the trailing propeller, whereby to createthe desired gaseous envelope for reducing BTF friction.

In yet another form of the invention, a supply of friction-reducingfluid (e.g., detergent) can be connected to the aforementioned smallopenings 275, whereby to create the desired friction-reducing envelopeabout BTFs 200.

In another form of the present invention, one or more baffle plates maybe provided about some or all of the circumference of BTFs 200 forproducing an encompassing gaseous envelope about BTFs 200, whereby toreduce hull friction and thereby increase the speed of the vessel. Moreparticularly, and looking now at FIGS. 15G-15L, in one preferred form ofthe invention, a baffle plate 700 is mounted to each BTF 200 just aft ofthe two counter-rotating propellers 265, 270. The baffle plate 700protrudes into the water coming off the propellers and flowing alongsidethe BTF and creates a high-pressure zone in front of the baffle plateand a low-pressure zone immediately aft of the baffle plate, whereby tocreate a dense stream of supercavitated water (e.g., an envelope ofgaseous bubbles) immediately aft of the baffle plate. This dense streamof gaseous bubbles enhances the already-supercavitated water coming offthe two counter-rotating propellers, whereby to create an enhancedenvelope of gaseous bubbles for further reducing hull friction as thetrailing portions of the BTF pass through water.

In one form of the invention, baffle plate 700 is a single-piece platefixed to the BTF, and preferably extends about the entire circumferenceof the BTF. See FIGS. 15M and 15N.

And in one form of the invention, and looking now at FIGS. 15O, 15P, and15Q, baffle plate 700 can have a trailing surface characterized by anarcuate (i.e., curved) section 703. Alternatively, the trailing surfaceof baffle plate 700 can be characterized by a frustoconical section 703.

In another form of the invention, baffle plate 700 is a single-pieceplate which is pivotally mounted to the BTF. See FIGS. 15R and 15S.Pivotally mounting baffle plate 700 to the BTF can allow greater orlesser degrees of supercavitation to be created along different portionsof the baffle plate and hence different portions of the BTF. By way ofexample but not limitation, baffle plate 700 may be rotatable so as tocreate higher degrees of supercavitation (i.e., greater amounts ofgaseous bubbles) along the top portion of the BTF (to provide morereduced hull friction for movable struts 300), and lesser degrees ofsupercavitation (i.e., lesser amounts of gaseous bubbles) along thebottom portion of the BTF (to provide denser water beneath the BTF forbetter support for the craft). In addition, pivoting of baffle plate 700may also be used to provide steering or trim (in addition to, or as analternative to, the aforementioned spoilers 540).

In another form of the invention, baffle plate 700 comprises amulti-part plate, with each portion 700A, 700B, 700C, 700D of the baffleplate being separately movable relative to the BTF (e.g., by actuators705A, 705B, 705C, 705D). See FIGS. 15T and 15U. The provision ofseparately movable portions of baffle plate 700 can allow greater orlesser degrees of supercavitation (i.e., greater or lesser amounts ofgaseous bubbles) to be created along different portions of the baffleplate (and hence along different portions of the BTF). In addition,separately movable portions of baffle plate 700 can provide steering ortrim (in addition to, or as an alternative to, the aforementionedspoilers 540).

If desired, multiple baffle plates 700 can be provided for each BTF 200.See, for example, FIG. 15V, which shows a series of baffle plates 700arranged along the length of BTF 200.

In one form of the invention, the outer perimeter of baffle plate 700 iscircular, such as is shown in FIGS. 15G-15V. In another form of theinvention, the outer perimeter of baffle plate 700 is corrugated (orserpentine, or comprises a series of peaks and troughs, etc.). See FIG.15W. Forming the outer perimeter of baffle plate 700 in this mannerprovides a “corrugated” supercavitation envelope having a less denseboundary layer of non-supercavitated water around the BTF. As a result,because the surface area of the boundary layer between thesupercavitated water and the non-supercavitated water has been reduced,if the sidewall of the BTF should encounter the boundary layer ofnon-supercavitated water, reduced hull friction will result.

If desired, and looking now at FIGS. 15X-15Z and 15ZA-15ZD, baffle plate700 may be provided with means for ejecting air from the aft surface ofthe baffle plate. More particularly, in this form of the invention, oneor more grooves 710 may be formed in the aft surface 715 of baffle plate700. An air line 720 may be used to deliver air to grooves 715,whereupon the air is released into the gaseous envelope produced bybaffle plate 700, thereby enhancing the gaseous envelope and furtherreducing hull friction as the trailing portions of the BTF pass throughthe gaseous envelope. As seen in FIGS. 15ZC and 15ZD, grooves 710 may beprovided about the entire perimeter of baffle plate 700 (FIG. 15ZC) orabout only a portion of the perimeter of baffle plate 700 (FIG. 15ZD).If desired, a fluid other than air (e.g., another gas or a liquid) maybe ejected from grooves 710.

As will hereinafter be discussed, BTF 200 may also be used as the hullof a submarine, or as the hull of a torpedo, or as the hull of anunmanned drone, etc. In this respect it should be appreciated that thebaffle plate 700 may be utilized on these craft as well so as to enhancethe supercavitation effect used to reduce hull friction.

Furthermore, it should be noted that, if desired, the baffle plate 700may be used on submerged surfaces of substantially any water craft,including water craft using rear propulsion means such as rearpropellers, rear water jets, etc., so as to reduce hull drag andincrease the speed of the craft. By way of example but not limitation,the baffle plate 700 may be used on a rear propulsion SWATH vessel, arear propulsion submarine, a rear propulsion torpedo, a rear propulsionunmanned drone, etc.

And, if desired, baffle plate 700 can be movable relative to BTF 200such that baffle plate 700 can be disposed flush with the outer surfaceof BTF 200 and then deployed outwardly when the baffle effect isdesired. This construction can be highly advantageous in certaincircumstances, e.g., where the baffle plate 700 is to be provided on atorpedo which must be launched from a torpedo tube.

In one preferred form of the present invention, each BTF 200 is providedwith (i) two counter-rotating propellers 265, 270 which generate agaseous envelope about the perimeter of the BTF, (ii) at least oneventuri injection ring disposed aft of the two counter-rotatingpropellers 265, 270 which generates an additional gaseous envelope whichsupplements and enhances the gaseous envelope produced by the twoserially-mounted, counter-rotating propellers on the front end of BTFs200, and (iii) at least one baffle plate 700 disposed aft of the twocounter-rotating propellers 265, 270 which generates an additionalgaseous envelope which also supplements and enhances the gaseousenvelope produced by the two serially-mounted, counter-rotatingpropellers on the front end of BTFs 200.

In one preferred form of the invention, the at least one venturiinjection ring 276 is disposed aft of the two counter-rotatingpropellers 265, 270 and in front of the at least one baffle plate 700,in which case the gaseous envelope produced by the at least one venturiinjection ring 276 supplements and enhances the gaseous envelopeproduced by the two serially-mounted, counter-rotating propellers 265,270 on the front end of BTFs 200, and the gaseous envelope produced bythe at least one baffle plate 700 supplements and enhances the gaseousenvelope produced by the two serially-mounted, counter-rotatingpropellers 265, 270 and the gaseous envelope produced by the at leastone venturi injection ring 276.

In another preferred form of the invention, the at least baffle plate700 is disposed aft of the two counter-rotating propellers 265, 270 andin front of the at least one venturi injection ring 276, in which casethe gaseous envelope produced by the at least one baffle plate 700supplements and enhances the gaseous envelope produced by the twoserially-mounted, counter-rotating propellers 265, 270 on the front endof BTFs 200, and the gaseous envelope produced by the at least oneventuri injection ring 276 supplements and enhances the gaseous envelopeproduced by the two serially-mounted, counter-rotating propellers 265,270 and the gaseous envelope produced by the at least one baffle plate700.

In the foregoing disclosure, openings 275 (FIG. 15B) are provided forreleasing air just aft of the trailing propeller, whereby to create aneven more dense gaseous envelope for reducing BTF friction. As notedabove, a venturi injection ring 276 may be disposed about openings 275so as to enhance the release of air about the perimeter of BTF 200.Furthermore, grooves 710 may be formed in the aft surface 715 of baffleplate 700 so as to release air just aft of the baffle plate, whereby tocreate an even more dense gaseous envelope aft of baffle plate 700. Theair provided to openings 275 and/or grooves 710 may be ambient air(acquired via air intakes adjacent the command module or struts, or bysnorkels extending upward from BTFs 200). Alternatively, and looking nowat FIG. 15ZE, gas turbine engine 210 may be equipped with a heatexchanger 725 such that cooling water introduced into heat exchanger 725can be turned into steam which is then ejected from openings 275 and/orgrooves 710, whereby to enhance the gaseous envelope coming off the twocounter-rotating propellers 265, 270 and/or venturi injection ring 276and/or baffle plate 700. In this respect it should be appreciated thatreleasing steam from openings 275 and/or grooves 710 is highlydesirable, inasmuch as the steam is at a temperature and pressuresignificantly higher than the water flowing past BTF 200 and henceprovides a more robust gaseous envelope.

Rudderless System

Conventional rudders are continuously deployed in the water, so thatthey create friction and drag not only when being manipulated so as tochange the direction of the vessel, but also under normal operatingconditions. This friction and drag has a substantial detrimental effecton the speed of the vessel.

In contrast, and looking now at FIGS. 16-26, attack craft 5 providesforward and aft steering elements (or spoilers) 225 that are projectablefrom, and retractable into, the outer skin of hollow tubular structure205. In this respect it should be appreciated that each of the spoilers225 can be projected an adjustable amount outboard from hollow tubularstructure 205. Furthermore, command module 100 can be provided withvarious control systems which permit each of the spoilers 225 to beoperated in a coordinated fashion or, if desired, independently from oneanother.

In one preferred form of the invention, sixteen spoilers 225 areprovided: four spoilers 225 at the front of each BTF 200 and fourspoilers 225 at the rear of each BTF 200, with spoilers 225 beingdisposed at the “12 o'clock”, “3 o'clock”, “6 o'clock”, and “9 o'clock”positions. This arrangement allows spoilers 225 to apply left, right, upand/or down forces (or any combination thereof) to the front and/or rearof each of the BTFs 200 while attack craft 5 is underway.

Spoilers 225 provide numerous significant advantages over conventionalrudders.

For one thing, spoilers 225 provide substantially no drag when thevessel is underway and no directional changes are needed—this is becausethe spoilers then reside flush with the outer skins of hollow tubularstructures 205. Spoilers 225 impose drag on the vessel only when theyare extended outwardly from the skins of hollow tubular structures 205,whereby to provide the forces necessary to maneuver the vessel—and theyare thereafter returned to their inboard (i.e., flush, and no-drag)positions as soon as the maneuver is completed and the vessel returns tostandard forward motion.

Additionally, and significantly, the provision of spoilers 225 on thefore and aft portions of hollow tubular structures 205 permits theapplication of more dramatic turning forces. More particularly, bysetting a fore spoiler to turn in one direction and a corresponding aftspoiler to turn in the opposite direction, significant turning forcescan be quickly and easily applied to the vessel using spoilers ofrelatively modest size. Thus, course corrections can be effectedquickly, making the vessel extremely agile, while permitting the turningfriction of the spoilers to be applied only for short durations.

Spoilers 225 can be used for turning left or right (see FIGS. 16-19),for adjusting the trim (i.e., the up/down attitude) of the vessel (seeFIGS. 20-23), and/or to enhance deceleration of the vessel (see FIGS.24-26).

Spoilers 225 can be flush plates that protrude from the outer skins ofhollow tubular structures 205 and cause friction when needed to changedirection. Alternatively, spoilers 225 can be made of an elastomericmaterial that can be inflated with air, fluids, etc. and which protrudefrom the outer skins of hollow tubular structures 205.

Fuel Tanks 220

Fuel tanks 220 are housed inside BTFs 200, preferably in the centersection 230. Fuel tanks 220 preferably comprise double-walled tanks madeof a flexible bladder material (e.g., a flexible bladder disposed insideanother flexible bladder). This arrangement allows for a fluid (e.g.,seawater) to be pumped into the outer bladder in order to compensate forthe consumption of fuel from within the inside bladder, thereby ensuringthat the buoyancy of the attack craft remains constant.

Center of Gravity

The center of gravity for attack craft 5 is intended to be as low aspossible, in order to maximize vessel stability. This is achieved bypositioning heavy components such as engines 210 and fuel tanks 220within the BTFs, thereby lowering the vessel's center of gravity so asto be as close as possible to the midline of the BTFs. In this respectit will be appreciated that turbine engines 210 and fuel tanks 220constitute approximately ⅔ of the total vessel weight and, due to theconstruction of attack craft 5, this weight is disposed entirely belowthe waterline. This leads to enhanced vessel stability.

Connecting Struts 300

As noted above, connecting struts 300 attach BTFs 200 to command module100. As also noted above, struts 300 are designed to be fixed to BTFs200 and pivot on command module 100 so as to allow attack craft 5 toassume different configurations (FIGS. 4, 7 and 8), whereby to permitcommand module 100 to sit different distances from the water. As seen inFIGS. 27-36, struts 300 comprise hydraulic or electric jack screws 305connected to load arms located within struts 300, whereby to move struts300 relative to command module 100. In this respect it will beappreciated that FIGS. 27-29 show struts 300 in a position correspondingto the attack craft configuration shown in FIG. 4, FIGS. 30-32 showstruts 300 in a position corresponding to the attack craft configurationshown in FIG. 7, and FIGS. 33-36 show struts 300 in a positioncorresponding to the attack craft configuration shown in FIG. 8.

Since struts 300 extend into the water, it is important to keep thestruts as thin as possible so as to minimize drag.

It should also be appreciated that the structural integrity of struts300 relies primarily on the strength of the load arms located within thestruts acting in conjunction with the outer skin of the struts, whileusing minimal internal frames. This is important, since struts 300 needto have large areas of uninterrupted volume in order to permit engineintake to pass uninterrupted through the interior of the struts.

Fly-by-Wire Controls

In one preferred form of the invention, sensors are located on hull-likebottom surface 110 of command module 100 and continuously measure thedistance of the command module from the water surface. A computerautomatically adjusts the disposition of struts 300 so as to maintainthe command module a desired distance above the water surface. In thisrespect it will be appreciated that, particularly when attack craft 5 isoperating at high speeds (e.g., 80 knots) in open water, it is importantto keep command module 100 from coming into contact with the surface ofthe water (and particularly important to keep command module 100 fromcoming into contact with the irregular sea swells commonly found in theopen sea).

Thus, for example, in standard seas, attack craft 5 may be placed in theconfiguration shown in FIG. 4 so that command module 100 is safely outof the water and the vessel has modest radar, infrared and visualsignatures.

However, in high seas, while operating at high speed, attack craft 5 maybe placed in the configuration shown in FIG. 7 so that command module100 stands well out of the water and is free from the affect of swells.

Furthermore, depending on sea conditions, attack craft 5 may be placedin a selected configuration between those shown in FIGS. 4 and 7.

Attack craft 5 is also designed to operate in stealth mode, by loweringits physical profile. In this case, attack craft 5 may be placed in theconfiguration shown in FIG. 8 so that command module 100 sits justabove, or actually in, the water, reducing its radar, infrared andvisual signatures. This mode can be very useful when attack craft 5 isbeing used for reconnaissance purposes and/or to deliver small teams ofspecial forces behind enemy lines and/or to extract the same.

Thus, in one preferred form of the invention, attack craft 5 is normallyoperated in the configuration shown in FIG. 4, with command module 100completely out of the water, but the command module being as low aspossible so as to have a reduced profile. However, in high seas and athigh speed, attack craft 5 may be operated in the configuration shown inFIG. 7, so that command module 100 stands well clear of any swells. And,when desired, attack craft 5 can be operated in the configuration shownin FIG. 8 so as to assume a stealth mode.

Or, attack craft 5 may be operated in a selected configuration betweenthose shown in FIGS. 4, 7 and 8.

Preferably, speed sensors feed speed data to a main computer, whichadjusts the sensitivity of the steering controls so that, whiletravelling at low speeds, the controls are more reactive and whentravelling at high speeds, the controls are less reactive. In otherwords, the main computer preferably adjusts the sensitivity of thesteering controls so that (i) large movements of the steering controls(e.g., a joystick) are required at high speeds to make modest changes inthe disposition of spoilers 225, and (ii) small movements of thesteering controls are required at slow speeds to make significantchanges in the disposition of spoilers 225. This construction eliminatesthe possibility that a modest movement of the controls at high speedwill result in a catastrophic change in the direction or attitude of thecraft.

Extendable BTF Boom

If desired, BTFs 200 can be provided with an extendible boom. This boomis deployable from the trailing end of the BTF, and is preferablyflexible. The extendible boom can serve two purposes.

First, the extendible boom can have controllable surface protrusionsalong its length that can be enlarged or contracted so as to allow dragto be applied to the boom, thus further stabilizing the BTF in a mannersimilar to the tail of a kite. The protrusions cause drag thatstabilizes the vessel in both the horizontal and vertical planes. Theprotrusions can be controlled by elastic bladders which are inflated soas to increase size (and hence drag) as desired, or a mechanical devicelocated at the end of the boom that provides mechanical drag resistance,thereby increasing stability.

Second, the extendible boom can also house sonar, listening devices,magnetometers, gravity interruption sensors, etc. that can be used forthe identification of submerged objects. By mounting these devices onthe end of an extendible boom, the devices can be isolated from theremainder of attack craft 5, so as to minimize interference with devicefunction.

Supercavitating Air Outlet Holes Formed in the Hull of the BTF and/orAir Trap Fins Formed Along the Hull of the BTF for Constraining Movementof the Supercavitated Air Skirt Relative to the Hull of the BTF

As described above, the present invention comprises a high speed SWATHboat with underwater hull friction reduction. Creating an air skirtaround the hull of the buoyant tubular foil (i.e., bypropeller-generated supercavitation and, optionally, by ejecting airthrough the hull and into the flow of water around the hull) displaceswater from around the hull and replaces it with a dense stream of airbubbles, thereby allowing the hull to ride through a cushion of densefoam air bubbles. Inasmuch as water generates 800 to 1000 times morefriction with a hull than air, the provision of an air skirt surroundingthe hull of the buoyant tubular foil (BTF) dramatically reduces frictionas the hull moves.

However, it will be appreciated that inasmuch as air is lighter thanwater, the air bubbles (created by the propeller-supercavitation and,optionally, by ejecting air out of the hull) tend to rise as soon asthey are formed. This upward movement of the air skirt can reducecoverage of the hull by the air skirt.

Thus, it is desirable to keep the air bubbles traveling horizontallyalong the hull as long as possible, so as to maintain coverage of thehull by the air curtain and thereby decrease hull friction as the hullmoves. Ideally, a complete skirt of air should be maintained about theentire perimeter of the hull so as to minimize hull friction. However,even an incomplete air skirt will act to reduce hull friction. At 50knots, a 60 foot long structure passes through the bubble region in onesecond, so anything which increases the amount of time that the aircurtain remains in contact with the hull provides an important benefit.Thus, even a 1/10 second increase in the time that a bubble spends incontact with the hull results in substantial friction reduction for thebuoyant tubular foil (BTF).

The following identifies various ways in which the air curtain may bemaintained for a longer period of time against the hull:

1. As noted above, the air skirt is created around the hull of thebuoyant tubular foil (BTF) by propeller-generated supercavitation and,optionally, by ejecting air through the hull and into the flow of wateraround the hull. Thus, in one form of the invention, the hull isprovided with many air outlet holes 405 for ejecting air out of the hulland supplementing the propeller-generated supercavitation bubble stream.Preferably, these air outlet holes 405 extend horizontally along thelength of the buoyant tubular foil 200, ensuring that the air curtaincovers substantially the entire length of the hull of BTF 200. See FIGS.37 and 37A-37C. Air ejection holes 405 may also be provided on struts300, e.g., on the leading edge of the struts (see FIGS. 37, 37B and37C).

2. Additionally, the hull of BTF 200 is also provided with a pluralityof horizontally-extending air trap fins 410. Air trap fins 410 channelthe air bubbles along the length of the hull and retard movement of theair bubbles away from the hull. See FIGS. 37 and 37A-37C.

3. If desired, air trap fins 410 may be contoured (FIG. 37) so as toforce the rising air bubbles to follow a tortuous path to escape awayfrom the hull of the BTF.

4. If desired, air trap fins 410 may be disposed in a spiralconfiguration around the hull of the BTF (FIG. 37) so as to definebubble channels along the hull of the BTF, whereby to cause the airbubbles to be trapped and constrained against the hull of the BTF as theair bubbles defuse along the channel.

5. Air trap fins 410 may be of a scallop-type design, thereby providingrecessed channels along the hull of the BTF, whereby to hold the airagainst the hull of the BTF.

6. It should be appreciated that the provision of air trap fins 410helps provide a water-flow boundary around the circumference of theunderwater hull (FIGS. 37 and 37A-37D). This water-flow boundarycomprises a water density gradient extending between dense sea water(spaced from the BTF) and an air and water mixture (adjacent to theBTF). The height of the air trap fins 410 helps determine the thicknessof the water-flow boundary layer. It should be appreciated that theheight of the air trap fins 410 can be adjusted (e.g., proportionally orotherwise) according to the length of the hull, e.g., for a shorterhull, the air trap fins may be shorter, and for a longer hull the airtrap fins may be taller.

7. Air trap fins 410 may run for only a portion of the length of thehull or for the entirety of the length of the hull, and may be radiallydistributed on all surfaces (FIGS. 37A and 37C).

8. If desired, air trap fins 410 may be radially distributed, except forthe bottom ¼ to ½ of the underside of the BTF hull (FIGS. 37 and 37D).In this case, the air curtain provided beneath the hull of the BTF willdissipate more rapidly, thereby allowing the bottom of the hull to rideon dense water and sheathing the remainder of the hull in an air/waterbubble stream. This configuration can provide better support for thecraft, inasmuch as the water beneath (and supporting) the craft isrelatively free of air and hence substantially not compressible underthe weight of the craft.

Single Propeller Cavitation

In an alternative embodiment of the present invention, and looking nowat FIG. 37E, the marine vessel propeller system comprises a singlepropeller 415 placed at the bow of a buoyant tubular foil 200. Thepropeller 415 is sized and configured such that, in operation, thepropeller creates and dispenses rearwardly an intense stream ofsupercavitated water which envelopes the hull of the buoyant tubularfoil, which is also preferably provided with air trap fins as previouslydescribed, and operative to prevent immediate escape of thesupercavitated water from the buoyant tubular foil (BTF) 200. Again,steering may be provided by spoilers as previously disclosed herein or,alternatively, by conventional rudders 420 (and, optionally, planes 425)as shown in FIG. 37E.

Submarine, Torpedo and Unmanned Submersible Craft Embodiments

In the foregoing disclosure, there is disclosed a novel fleet protectionattack craft 5 which generally comprises a command module 100 forcarrying crew, weapons and payload (including passengers), a pair ofbuoyant tubular foils (BTFs) 200 for providing buoyancy, propulsion andsteering, and a pair of struts 300 for supporting command module 100 onBTFs 200.

It is further within the scope of the present invention to provide anovel submersible water craft (which may also sometimes hereinafter bereferred to herein as a vehicle or vessel, with the terms craft, vehicleand/or vessel meant to be interchangeable), such as a submarine and/or atorpedo and/or an unmanned drone, etc. which utilizes a single (buoyant)tubular hull, generally of the sort disclosed above in connection withbuoyant tubular foil (BTF) 200, as the hull of the submersible watercraft (e.g., submarine, torpedo, unmanned drone, etc.). For the purposesof the present invention, such a tubular hull may be considered to be abuoyant tubular foil (BTF), and may sometimes be so referred to herein.

In one form of the present invention, and referring now to FIG. 38,there is provided a submarine 430 which comprises a tubular hull (i.e.,BTF) 435, and front-pulling propeller or propellers 440 for providingpropulsion and an air skirt (supercavitation) for engulfing the hull ofthe submarine in the manner previously discussed. Again, steering forthe submarine may be provided by spoilers as previously discussed or,alternatively, rudders 420 (and, optionally, planes 425) as shown inFIG. 38.

By way of example but not limitation, and looking now at FIGS. 38A, 38B,38C and 38D, there is shown a novel submarine 500 formed in accordancewith the present invention. Novel submarine 500 is uniquely suited torapidly and covertly deploying small teams of personnel to any coastlinein the world.

More particularly, submarine 500 generally comprises a tubular hull(i.e., BTF) 505 having a conning tower 510 extending upwards therefrom,and including a pilot cockpit 515, crew quarters 520, an engine room525, and an area 530 for storing fuel (e.g., in fuel tanks and/or fuelbladders, etc., not shown) and/or other cargo (e.g., weapons).

Submarine 500 also comprises front-pulling propeller or propellers 535for providing propulsion and an air skirt (supercavitation) forengulfing the hull of the submarine in the manner previously discussed,and spoilers 540 for providing steering in the manner previouslydiscussed. Preferably, a pair of counter-rotating propellers 535 areused, with the pair of counter-rotating propellers being arranged tocancel out any rotational forces which might induce the submarine tospin on its lengthwise axis. Additionally, submarine 500 preferablycomprises nozzles 545 disposed just aft of propeller(s) 535, and alsodisposed on the front edges of conning tower 510, for ejecting fluids(e.g., gases and/or low friction liquids) from the submarine and intothe flow of water around the submarine, whereby to further reducefriction as the submarine moves through the water. Submarine 500preferably also comprises a pair of horizontal stabilizers 550 forproviding additional attitude control for the submarine, e.g, while thesubmarine is operating at low speeds. Horizontal stabilizers 550 arepreferably retractable into hull 505 for reduced friction when thesubmarine is running at high speeds.

In this form of the invention, a gas turbine engine 555, aspiratedthrough a telescoping snorkel 560, is provided for high speed propulsionwhen the submarine is running on the surface of the water or at a depthshallow enough for snorkel 560 to function. An electric motor 565,powered by batteries 570, is provided for propulsion when the submarineis submerged below snorkel depth and/or when the submarine requires“silent” running (e.g., for covert operations).

Ballast tanks (not shown) of the sort well known in the art are providedfor regulating the buoyancy of the submarine in the water.

An air lock 575 is preferably provided in hull 505 in order to permitdivers to exit and enter the hull while the submarine is submerged.Alternatively, an air lock (not shown) may be provided in conning tower510 for access via top hatch 580.

If desired, retractable wheels 585 may be provided so as to render thesubmarine amphibious.

In one preferred manner of use, submarine 500 travels through the oceanat high speeds, powered by its gas turbine engine 555, which isaspirated through telescoping snorkel 560. This is preferably done withthe submarine operating fully submerged at snorkel depth, although itmay also be done with the conning tower 510 protruding above the surfaceof the water while the hull 505 is submerged below the surface of thewater. Front-pulling propeller(s) 535, which provide both propulsion andan air skirt (supercavitation) for engulfing the hull of the submarine,and spoilers 540 for providing steering, make such high speed operationpractical and efficient. Additionally, nozzles 545 (disposed just aft ofpropeller(s) 535, and also disposed on the front edges of conning tower510) eject fluids (e.g., gases and/or low friction liquids) from thesubmarine and into the flow of water around the submarine, whereby tofurther reduce friction as the submarine moves through the water. Duringsuch high speed operation, horizontal stabilizers 550 are preferablyretracted into hull 505 for reduced friction.

If and when it is necessary to evade detection, the submarine cansubmerge below snorkel depth and switch to battery power. While thistypically results in limited operating time and/or in slower operatingspeeds due to the limited onboard battery capacity, it allows thesubmarine to operate substantially silently. When operating at loweroperating speeds, horizontal stabilizers 550 may be used to enhanceattitude control.

When the submarine is to approach a shoreline (e.g., to deploy a covertteam of personnel), the submarine can operate on battery power so as tominimize noise and avoid detection.

Personnel can exit and enter the submarine while the submarine issubmerged via air lock 575 and/or top hatch 580.

If desired, batteries 570 may be replaced by, and/or supplemented by,fuel cells of the sort known in the art.

In another form of the invention, and referring now to FIG. 39, a singletubular structure (BTF), such as a body 445 of a torpedo 450, may beprovided with a warhead (e.g., detonator and high explosives) andprovides for buoyancy (including negative buoyancy where desired),propulsion and steering, as is known in the art. More particularly, inthis form of the invention, buoyancy is preferably provided by ballasttanks contained within the body 445 of the torpedo 450. Propulsion isprovided by at least one front-pulling propeller 455 of the sortdisclosed above, and an electric motor contained within the body 445 ofthe torpedo 450, with the front-pulling propeller or propellers 455providing an air skirt (supercavitation) around the body 445 of thetorpedo 450 during movement of the torpedo through water, in the mannerpreviously disclosed. Again, steering may be provided by spoilers aspreviously disclosed herein or, alternatively, rudders 420 (and,optionally, planes 425) as shown in FIG. 39.

In another form of the present invention, and referring now at FIG. 40,there is shown a novel unmanned submersible craft 600 formed inaccordance with the present invention. Novel unmanned submersible craft600 is uniquely suited to rapidly and covertly enter areas where it isnecessary to gather visual, electronic (including radar and sonar)and/or chemical data in order to assess a situation.

More particularly, unmanned submersible craft 600 generally comprises atubular hull (i.e., BTF) 605 having an equipment area 620, an engineroom 625, and an area 630 for storing fuel (e.g., in fuel tanks and/orfuel bladders, etc., not shown) and/or other cargo (e.g., weapons).

Unmanned submersible craft 600 also comprises front-pulling propeller orpropellers 635 for providing propulsion and an air skirt(supercavitation) for engulfing the hull of the unmanned submersiblecraft in the manner previously discussed, and spoilers 640 for providingsteering in the manner previously discussed. Preferably, a pair ofcounter-rotating propellers 635 are used, with the pair ofcounter-rotating propellers being arranged to cancel out any rotationalforces which might induce the submarine to spin on its lengthwise axis.Additionally, unmanned submersible craft 600 preferably comprisesnozzles 645 disposed just aft of propeller(s) 635 for ejecting fluids(e.g., gases and/or low friction liquids) from the unmanned submersiblecraft and into the flow of water around the unmanned submersible craft,whereby to further reduce friction as the unmanned submersible craftmoves through the water. Unmanned submersible craft 600 preferably alsocomprises a pair of horizontal stabilizers 650 (only one of which isshown in FIG. 40) for providing additional attitude control for theunmanned submersible craft, e.g, while the unmanned submersible craft isoperating at low speeds. Horizontal stabilizers 650 are preferablyretractable into hull 605 for reduced friction when the unmannedsubmersible craft is running at high speeds.

In this form of the invention, a gas turbine engine 655, aspiratedthrough a pivotally-retractable or telescoping snorkel 660, is providedfor high speed propulsion when the unmanned submersible craft is runningon the surface of the water or at a depth shallow enough for snorkel 660to function. An electric motor 665, powered by batteries 670, isprovided for propulsion when the unmanned submersible craft is submergedbelow snorkel depth and/or when the unmanned submersible craft requires“silent” running (e.g., for covert operations).

Ballast tanks (not shown) of the sort well known in the art are providedfor regulating the buoyancy of the unmanned submersible craft in thewater.

It is intended that unmanned submersible craft 600 be able to gathervisual, electronic (including radar and sonar) and/or chemical data inthe area around the craft. This typically means gathering visual,electronic and/or chemical data from above the surface of the water,although in some circumstances it may also involve gathering visual,electronic and/or chemical data from below the surface of the water. Inone preferred form of the invention, the visual, electronic and/orchemical data is gathered from above the surface of the water while theunmanned submersible craft remains in a submerged condition so as tominimize the possibility of detection. To this end, the visual,electronic and/or chemical sensors are preferably adapted to be advancedfrom the unmanned submersible craft to a position above the surface ofthe water while the unmanned submersible craft remains below the surfaceof the water. This may be done by mounting visual, electronic and/orchemical sensors to snorkel 660 so that visual, electronic and/orchemical sensors project above the surface of the water while snorkel660 is in its deployed condition. Additionally, visual, electronicand/or chemical sensors may be mounted to a telescoping mast (not shown)or floating buoy (not shown) housed within a deployment chamber 675 inorder that the visual, electronic and/or chemical sensors may be raisedto the surface of the water while the unmanned submersible craft remainsbelow the surface of the water. In addition to the foregoing, visual,electronic and/or chemical sensors may be mounted in nose cone 680,and/or tail cone 685, so that visual, electronic and/or chemical datacan be gathered by the unmanned submersible craft.

In one preferred manner of use, unmanned submersible craft 600 travelsthrough the ocean at high speeds, powered by its gas turbine engine 655,which is aspirated through telescoping snorkel 660. This is done withthe unmanned submersible craft operating fully submerged at snorkeldepth. Front-pulling propeller(s) 635, which provide both propulsion andan air skirt (supercavitation) for engulfing the hull of the unmannedsubmersible craft, and spoilers 640 for providing steering, make suchhigh speed operation practical and efficient. Additionally, nozzles 645(disposed just aft of propeller(s) 635) eject fluids (e.g., gases and/orlow friction liquids) from the unmanned submersible craft and into theflow of water around the unmanned submersible craft, whereby to furtherreduce friction as the unmanned submersible craft moves through thewater. During such high speed operation, horizontal stabilizers 650 arepreferably retracted into hull 605 for reduced friction.

If and when it is necessary to evade detection, the unmanned submersiblecraft 600 can submerge below snorkel depth and switch to battery power.While this typically results in limited operating time and/or in sloweroperating speeds due to the limited onboard battery capacity, it allowsthe unmanned submersible craft to operate substantially silently. Whenoperating at lower operating speeds, horizontal stabilizers 650 may beused to enhance attitude control.

Alternatively, and/or additionally, the unmanned submersible craft maybe carried by an aircraft to an area closer to its final destination,and then dropped from the aircraft, so as to shorten the distance to betraveled by the unmanned submersible craft and still maintain itsstealth approach.

When the unmanned submersible craft has reached the area in which it isto gather visual, electronic and/or chemical data, it preferably remainssubmerged and runs under battery power, except for short periods of timewhen it may rise to snorkel depth and run under its gas turbine engine655 so as to recharge its batteries. With the unmanned submersible craftremaining submerged, visual, electronic and/or chemical data is gatheredby the sensors carried by the craft, e.g., from above the surface of thewater by raising sensors to the surface by a telescoping mast (notshown) or a floating buoy (not shown) projected from deployment chamber675, and/or from below the surface of the water via the sensors carriedby nose cone 680 and/or tail cone 685.

Alternatively, and/or additionally, the unmanned submersible craft mayreposition itself into a vertical orientation (e.g., in the manner shownin FIG. 41) so that tail cone 685 projects above the surface of thewater, such that the sensors in tail cone 685 may be used to acquirevisual, electronic and/or chemical data from above the surface of thewater.

The data acquired by the unmanned submersible craft may then betransmitted back to a base station by conventional radio transmission ofthe sort well known in the art.

If desired, batteries 670 may be replaced by, and/or supplemented by,fuel cells of the sort known in the art.

And if desired, nose cone 680, and/or tail cone 685, and/or hull 605,may carry fittings for permitting refueling of the unmanned submersiblecraft from a fuel source (e.g., a surface vessel, a submarine, a remoterefueling module, etc.).

Front Pulling Propeller Mechanism

It should be appreciated that with the preferred form of the presentinvention, a front pulling propeller mechanism is used to both (i) pullthe buoyant tubular foil (BTF) 200 (or other tubular structure) thoughthe water, and (ii) generate the friction-reducing air curtain whichengulfs the trailing BTF 200 (or other tubular structure). Thus, thesame element (i.e., the front pulling propeller mechanism) is used tosimultaneously provide both propulsion and the supercavitatingfriction-reducing air curtain. As noted above, each of these aspectsprovides significant improvements in propulsion efficiencies, with (i)the front pulling propeller mechanism biting into virgin water, whichenhances the propulsion action of the propeller mechanism, and (ii) thefront pulling propeller mechanism providing the supercavitatingfriction-reducing air curtain which reduces hull friction as the BTF 200(or other tubular structure) moves through the water. Uniquely, thefront pulling propeller mechanism is used to simultaneously provide bothof these functions.

Significantly, the same approach is used regardless of whether the BTF200 (or other tubular structure) is part of a SWATH surface vessel, oris the hull of a submarine or other submersible vessel, or is thefuselage of another form of submersible vehicle such as a torpedo orunmanned drone. In other words, with the preferred form of the presentinvention, the front pulling propeller mechanism simultaneously providesits dual function (i.e., propulsion and the supercavitatingfriction-reducing air curtain) for the elongated hull structure (i.e.,the BTF 200 or other tubular structure) which trails the front pullingpropeller mechanism. In this way, the elongated hull structure is movedthrough the water with great efficiency and hence significantlyincreased speed.

It will be appreciated that it is important that the front pullingpropeller mechanism be configured (e.g., blade shape, blade size, numberof blades employed, counterrotation of the blades if more than one bladeis provided, etc.) and operated (e.g., blade rotation speed, etc.) forboth efficient propulsion and efficient air curtain generation. In thislatter respect, it will be appreciated that the propeller mechanismshould generate an air curtain of sufficient size and volume to engulfall (or substantially all) of the perimeter of the trailing hullstructure (e.g., the BTF 200). In this respect it will be appreciatedthat not all front pulling propeller mechanisms will generate thesupercavitating friction-reducing air curtain desired in the presentinvention. By way of example but not limitation, a propeller rotatingrelatively slowly will generate minimal supercavitation function (whichmay be a desired design feature, such as on a ballistic missilesubmarine which may give a priority to noise reduction). By way offurther example but not limitation, a relatively small propeller maythrow off a bubble stream, but the bubble stream may not be large enoughto engulf the perimeter of the trailing hull structure and therebyprovide the desired air curtain about the outer surface of the trailinghull structure. Thus it will be appreciated that attention must be paidto the configuration of the front pulling propeller mechanism (e.g.,blade shape, blade size, number of blades employed, counterrotation ofthe blades if more than one blade is provided, etc.) and to theoperation of the front pulling propeller mechanism (e.g., blade rotationspeed, etc.) in order to provide the desired supercavitatingfriction-reducing air curtain for the trailing hull structure.Appropriate design and operational parameters will be apparent to thoseskilled in the art in view of the present disclosure.

In one preferred form of the invention, the front pulling propellermechanism comprises a pair of counterrotating propellers to efficientlyprovide both propulsion and the supercavitating friction-reducing aircurtain, with the propellers having a diameter which is approximately 33percent to approximately 90 percent of the diameter of the trailing BTF,and most preferably approximately 66 percent of the diameter of thetrailing BTF 200 (or other tubular structure), and a rotation speed ofapproximately 2000 to approximately 3500 revolutions per minute (rpm),and most preferably approximately 3000 revolutions per minute (rpm).

Non-Military and Civilian Applications

In the foregoing description, attack craft 5 is described in the contextof its use for military applications. However, it should be appreciatedthat attack craft 5 may also be used for other, non-militaryapplications such as security applications (e.g., police, immigrationand drug enforcement purposes), public safety applications (e.g., searescues), high-speed servicing and re-supply applications (e.g., forservicing oil drilling platforms), high-speed water taxi applications,private pleasure craft applications, etc.

Modifications of the Preferred Embodiments

It should be understood that many additional changes in the details,materials, steps and arrangements of parts, which have been hereindescribed and illustrated in order to explain the nature of the presentinvention, may be made by those skilled in the art while still remainingwithin the principles and scope of the invention.

What is claimed is:
 1. A marine vessel comprising: at least one buoyanttubular foil; and at least one baffle plate positioned about theperimeter of the at least one buoyant tubular foil so as to protrudeinto the flow of water passing by the perimeter of the at least onebuoyant tubular foil, whereby to create a high-pressure zone fore of theat least one baffle plate and a low-pressure zone immediately aft of theat least one baffle plate, whereby to create a dense stream ofsupercavitated water immediately aft of the at least one baffle plate.2. A marine vessel according to claim 1 wherein the at least one baffleplate comprises a unibody baffle plate.
 3. A marine vessel according toclaim 2 further comprising apparatus for moving the unibody baffle platerelative to the at least one tubular foil.
 4. A marine vessel accordingto claim 1 wherein the at least one baffle plate comprises a multi-partbaffle plate.
 5. A marine vessel according to claim 4 wherein each partof the multi-part baffle plate is separately movable relative to the atleast one buoyant tubular foil.
 6. A marine vessel according to claim 5further comprising apparatus for moving each part of the multi-partbaffle plate.
 7. A marine vessel according to claim 1 wherein the atleast one baffle plate comprises a plurality of baffle plates disposedserially along the at least one buoyant tubular foil.
 8. A marine vesselaccording to claim 1 wherein the at least baffle plate extends about thecomplete circumference of the at least one buoyant tubular foil.
 9. Amarine vessel according to claim 1 wherein the at least one baffle plateextends about only a portion of the circumference of the at least onebuoyant tubular foil.
 10. A marine vessel according to claim 1 whereinthe at least one baffle plate is selectively projectable relative to theouter surface of the at least one buoyant tubular foil, such that the atleast one baffle plate can be (i) retracted so as to be disposed flushwith the outer surface of the at least one buoyant tubular foil, and(ii) projected into the flow of water moving past the outer surface ofthe at least one buoyant tubular foil.
 11. A marine vessel according toclaim 1 wherein the at least one baffle plate comprises means forreleasing a fluid from a trailing surface of the at least one baffleplate.
 12. A marine vessel according to claim 1 wherein the at least onebuoyant tubular foil comprises at least one propeller for moving the atleast one buoyant tubular foil through water.
 13. A marine vesselaccording to claim 12 wherein the at least one propeller is disposedfore of the at least one baffle plate.
 14. A marine vessel according toclaim 12 wherein the at least one propeller is disposed aft of the atleast one baffle plate.
 15. A marine vessel according to claim 1 whereinthe marine vessel comprises a surface vessel.
 16. A marine vesselaccording to claim 15 wherein the surface vessel comprises: a commandmodule; first and second buoyant tubular foils; and first and secondstruts for connecting the first and second buoyant tubular foils to thecommand module, respectively; wherein each buoyant tubular foilcomprises at least one baffle plate.
 17. A marine vessel according toclaim 1 wherein the marine vessel is submersible.
 18. A marine vesselaccording to claim 17 wherein the marine vessel comprises one from thegroup consisting of a submarine, a torpedo, and an unmanned drone.
 19. Amarine vessel according to claim 1 further comprising: at least oneventuri injection ring positioned adjacent to the perimeter of the atleast one buoyant tubular foil so as to create a passageway between theat least one venturi injection ring and the perimeter of the at leastone buoyant tubular foil, wherein the passageway is characterized by afore opening, an aft opening, and an intermediate opening disposedbetween the fore opening and the aft opening, and wherein theintermediate opening is smaller than the fore opening and the aftopening; at least one air opening formed in the perimeter of the atleast one buoyant tubular foil adjacent to at least one of theintermediate opening and the aft opening; and at least one passagewayconnecting the at least one air opening to a source of air.
 20. A methodfor moving through water, the method comprising: providing a marinevessel comprising: at least one buoyant tubular foil; and at least onebaffle plate positioned about the perimeter of the at least one buoyanttubular foil so as to protrude into the flow of water passing by theperimeter of the at least one buoyant tubular foil, whereby to create ahigh-pressure zone fore of the at least one baffle plate and alow-pressure zone immediately aft of the at least one baffle plate,whereby to create a dense stream of supercavitated water immediately aftof the at least one baffle plate; and moving the marine vessel throughwater, such that the passage of water past the at least one baffle platecreates a high-pressure zone fore of the at least one baffle plate and alow-pressure zone immediately aft of the at least one baffle plate,whereby to create a dense stream of supercavitated water immediately aftof the at least one baffle plate.